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M P- 7 Does That Stand For " Money Pit"


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Cam and Injector cups were under warranty but now turbo and SRA problems are killing me. Also I'm om the 5th $81 pyro temp stick sensor. Engine fault coded last week on my '07 Granite Quad Dump.

Took it to local MACK dealer shop. They showed me the SRA fault and said replacement was necessary and extended warranty of 3000 hours was OUT. SRA around $800 cost and a few hundred labor but they recommended a $3300 turbo to FIX the deal and 7 hours labor.

I got the turbo off and had it rebuilt ($400), balanced, bearings, and all and they found it had no problem in it...put it back on ($210 install kit) and went to MACK shop for new SRA and calibration. $1240.. around the block and back to shop.... same problem. Shut down codes and extreme Pyro temp, barking sputter though infrequent, and a screaming turbo.

Tech spent 3 hours hunting the Pyro short to no avail, finally chained it down on the rollers and run her on the computer for a bit.

They used the turbo actuator plastic guage (tool) and came back with the turbo lever was about 2 splines off full actuation or completed motion. I could see this with the gauge on the turbo with the actuator housing removed.. $297 more..

Now here is my question since the truck runs good with the Pyro sensor unplugged (and not running from 400 degrees to 1400 degrees in 5 seconds everytime you give it fuel or change gears).. Am I hurting the motor any if I do not fix this just right now..

The turbo shop said they will reposition the lever free when I can bring the turbo in but I need to work the truck till the next rainy spell if possible.

The truck running right is a horse no doubt but I have no confidence in this motor for the whole 120K I've had it.. With the Pyro sensor unplugged the MalFuc'n light is on but it has been on 1/2 the time anyway.... still needing to run it right now but do not want to hurt anything... GO or NO GO??

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Cam and Injector cups were under warranty but now turbo and SRA problems are killing me. Also I'm om the 5th $81 pyro temp stick sensor. Engine fault coded last week on my '07 Granite Quad Dump.

Took it to local MACK dealer shop. They showed me the SRA fault and said replacement was necessary and extended warranty of 3000 hours was OUT. SRA around $800 cost and a few hundred labor but they recommended a $3300 turbo to FIX the deal and 7 hours labor.

I got the turbo off and had it rebuilt ($400), balanced, bearings, and all and they found it had no problem in it...put it back on ($210 install kit) and went to MACK shop for new SRA and calibration. $1240.. around the block and back to shop.... same problem. Shut down codes and extreme Pyro temp, barking sputter though infrequent, and a screaming turbo.

Tech spent 3 hours hunting the Pyro short to no avail, finally chained it down on the rollers and run her on the computer for a bit.

They used the turbo actuator plastic guage (tool) and came back with the turbo lever was about 2 splines off full actuation or completed motion. I could see this with the gauge on the turbo with the actuator housing removed.. $297 more..

Now here is my question since the truck runs good with the Pyro sensor unplugged (and not running from 400 degrees to 1400 degrees in 5 seconds everytime you give it fuel or change gears).. Am I hurting the motor any if I do not fix this just right now..

The turbo shop said they will reposition the lever free when I can bring the turbo in but I need to work the truck till the next rainy spell if possible.

The truck running right is a horse no doubt but I have no confidence in this motor for the whole 120K I've had it.. With the Pyro sensor unplugged the MalFuc'n light is on but it has been on 1/2 the time anyway.... still needing to run it right now but do not want to hurt anything... GO or NO GO??

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Is it a pre-dpf mp7? If so it wont hurt a thing.

Also if its an 04 emissions MP7, have they put the updated jumper harness and pyrometer sensor on it?

Yes on pre-DPF and yes on updated harness, after the first one as it was under warranty.

If these aggravating qwirks were tended to without frothing at that $104 per hr labor rate they might have something.

Thank you for the reply and the "GO" for now vote. I watch the oil and water temp too much but with a haywire Pyro reading that is my release from worrying whats going on in there.

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We've also had issues with our '07 pre dpf mp7's. Both have had cams, under warranty thankfully. We've repaired leaks on the thermostat housings and multiple air leaks from push connect fittings between the chassis and cab because of the air lines being way too tight. Also experiencing poor fuel economy compared to our e7's.

Mack- Built Tough to Ride Rough!

Driver and operator for Bertils Gravel and Excavation

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I installed some automatic grease systems on three CTPs in (I think) 2006. Other than a few problems with camshafts and pyrometers on a couple of themthey haven't been nearly as bad as the '07 emissions MP8 engines.

"Mebbe I'm too ugly and stupid to give up!"

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Yes on pre-DPF and yes on updated harness, after the first one as it was under warranty.

If these aggravating qwirks were tended to without frothing at that $104 per hr labor rate they might have something.

Thank you for the reply and the "GO" for now vote. I watch the oil and water temp too much but with a haywire Pyro reading that is my release from worrying whats going on in there.

Best thing is to unplug it and drive on. Being unplugged it will make the code active for an open circuit sensor and not derate engine. If left plugged up and it starts pegging the guage the ECM could think it really is hot and derate the engine. We put alot of these sensors in the pre DPF MP-7's. We keep a box full on the parts shelf. The ones with the black connector are the "new style". Also there is a one year warranty on these sensors. If you paid a Mack dealer to put it in and it fails/acts up and sets a code within a year take the truck back with your proof of purchase and Mack will pay parts and labor to install it. We have one CTP that has come back 3 times in ayear all paid for. Also same thing with the humidity sensor on the air cleaner piping they seem to go out often as well.

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Best thing is to unplug it and drive on. Being unplugged it will make the code active for an open circuit sensor and not derate engine. If left plugged up and it starts pegging the guage the ECM could think it really is hot and derate the engine. We put alot of these sensors in the pre DPF MP-7's. We keep a box full on the parts shelf. The ones with the black connector are the "new style". Also there is a one year warranty on these sensors. If you paid a Mack dealer to put it in and it fails/acts up and sets a code within a year take the truck back with your proof of purchase and Mack will pay parts and labor to install it. We have one CTP that has come back 3 times in ayear all paid for. Also same thing with the humidity sensor on the air cleaner piping they seem to go out often as well.

Great info for me....thank you

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Great info for me....thank you

We have lots of pre DPF MP-7's running here. About 7 CXP's , 9 CTP tractors and 2 CTP dump trucks. One of the CTP dumps must be speced just right because it out runs and out pulls all the 427HP CV's around here and it only has a 395HP engine. We have replaced turbos and or actuators on most early on under warranty (nut would spin off the impeller shaft). Exhaust manifold gaskets do leak sometimes. The fuel filter stands go bad/plug up and cause low fuel pressure on a few. The EGR coolers sometimes leak, mostly external leaks but sometimes inside and wipes out the Mass Flow sensor just like the ASET engines do. Sometimes the Mas Flow sensor get wiped out by condensation the the EGR cooler, there is a reprogram/download for this. The worst thing we have seen is the oil pickup tube in the pan is a real long tube that is held up to the bottom of the block by a strap, sometimes this strap breaks and the pick up tube angles down to the bottom of the pan and sucks to the pan and causes a restriction of oil supply to the engine . This has happened to a few of the CXP's with forward sump oil pans. I cant remember if the CTP is forward sump or not. We havent seen any cam or injector cup problems here at our shop with the older MP-7s. There injector cup design was different/beter on the pre-DPF enines. The CTP tractors here are getting great MPG however they are turned down to 58MPH.

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